Choosing the right range

[angupa]

I have a general question:
when I'm developping an HPLC method, I could find that the linearity will be in a very wide range of concentration.
My question is how can I choose the best range of lineartiy to work in routine.
Guidelines in general said that it must be neccesary to work between the 80% and 120% of the unknown concentration but, I know that if I work near the LQ the accuracy of my results will be worst than if I work in another range more concentrated.

Best regards

[tom jupille]

No single answer because sample prep will also affect results (e.g., if you have do to a dilution, that will add 0.5% or so to your CV).

I'd go with whatever minimizes sample workup; anything between about 5X LLOQ and whatever gives you about 0.5AU peak height should be OK.